Atmospheric circulation patterns and teleconnections over southern South America in CMIP5 GCMs

0493295 - ÚFA 2019 DE eng A - Abstrakt
Stryhal, Jan - Hynčica, M. - Huth, Radan
Atmospheric circulation patterns and teleconnections over southern South America in CMIP5 GCMs.
EMS Annual Meeting Abstracts, Vol. 15. Berlín: European Meteorological Society, 2018.
[EMS Annual Meeting: European Conference for Applied Meteorology and Climatology 2018. 03.09.2018-07.09.2018, Budapest]
Institucionální podpora: RVO:68378289
Klíčová slova: atmospheric circulation * teleconnections * regional climate change scenarios * downscaling
Obor OECD: Meteorology and atmospheric sciences
https://meetingorganizer.copernicus.org/EMS2018/EMS2018-277.pdf

Global Circulation Models (GCMs) are fundamental tools for climate studies and provide the initial information
for the generation of regional climate change scenarios through dynamical and/or statistical downscaling.
The basic assumption of applying downscaling methods is that the main drivers of local climate conditions are
credibly simulated by GCMs. In this context, this study aims at evaluating the skill of a set of CMIP5 GCMs in
representing circulation types and teleconnection patterns in Southern South America. To this end, we test the
ability of GCMs to reproduce (a) sea level pressure patterns using several classification methods, including rotated
principal component analysis in a T-mode, several implementations of cluster analysis, Jenkinson-Collison
scheme, Lund’s correlation method, and circulation prototypes, and (b) mid tropospheric (500 hPa) circulation
in terms of teleconnection patterns (modes of low-frequency variability). Several reanalysis datasets are taken as
reference: NCEP/NCAR, ERA-40, JRA-55, 20CRv2, and ERA-20C. The validation analysis for circulation types
is performed in two domains, covering subtropical (20 - 40 S) and mid (40 – 60 S) latitudes of South America,
and focuses on the frequency of occurrence of the types and their lifetime (persistence). The teleconnection patterns
affecting southern South America, i.e. the Southern Annular Mode and two Pacific-South America patterns,
are considered. We demonstrate that the rank of GCMs regarding their ability to simulate atmospheric circulation
depends on the reference reanalysis and the classification method used. Therefore, we recommend that for a fair assessment
of atmospheric circulation in GCMs, multiple classifications and multiple reference datasets (reanalyses)
are required.
Trvalý link: http://hdl.handle.net/11104/0286682